I have successfully changed a background using the Layers feature. Part of that process was copying and pasting by Edit--Copy and Edit--Paste in Cs4. I've done it only once, and now that I am onto a new image that I'd like to copy, the Copy button is greyed out, and all I am allowed to select is Paste and when I select that, it only pastes the image I'd done the first time. I've closed out Photoshop twice, and it is still doing the same thing. I just want my Copy button back... Help??